1. Field of the Invention
The present invention generally relates to a mobile communication device with a side key and, more particularly, to a mobile communication device having a side key to which various functions can be differently and independently assigned according to a mode and a press time, and a method for controlling the function-assignable side key.
2. Description of the Related Art
With a remarkable growth of related technologies, mobile communication devices, e.g., a mobile phone, have become a necessary convenience of modern life. Moreover, to satisfy a variety of increasing demands of users, recent mobile communication devices have had various, specific, useful functions and applications in addition to their inherent and essential functions.
In general, such a mobile communication device has a key input system for producing input signals by press actions of a user. The key input system should have an appropriate interface for enabling a user to use various functions and applications of the device, and should offer a simple, convenient accessibility to execute such functions and applications. In view of these two sides, the key input system of the mobile communication device has continuously improved in key type, key configuration, key function, etc.
Most keys of the mobile communication device are typically disposed on the front of the mobile device body. Only a limited number of keys are disposed on the side of the mobile device body and they are called side keys. Representative one of the side keys is a volume key, which is composed of two buttons for turning up and down the volume. In order for a user to easily adjust voice volume during a call, the volume key is conveniently located on the side of the device body.
However, a conventional side key has a fixed, i.e., unvaried, function of its own. For example, the volume key produces input signals for executing just a natural function for adjusting the volume, e.g., voice volume, ring tone volume, etc., during either a call mode or an idle mode.
FIG. 1 shows, in a perspective view, a side key 12 of a conventional mobile communication device 10. In the example of FIG. 1, the side key 12 is the above-mentioned volume key and composed of function-fixed two buttons, namely, volume up and down buttons 12a and 12b, respectively.
Some conventional mobile communication devices may have another side key, such as a camera key, an MP3 play key, an auto answer key, etc. Such a side key is a kind of a shortcut or hot key for allowing a direct access to a specific application. However, such a side key as well executes only its own natural function, initially assigned and unvaried, and cannot execute several functions. Moreover, there is no side key that allows a user to freely establish and change the function associated with the key.